[Python-Dev] PEP 590 discussion (original) (raw)

Mark Shannon mark at hotpy.org
Sat Apr 27 05:19:15 EDT 2019


Hi Jeroen,

On 15/04/2019 9:38 am, Jeroen Demeyer wrote:

On 2019-04-14 13:30, Mark Shannon wrote:

PYVECTORCALLARGUMENTSOFFSET exists so that callables that make onward calls with an additional argument can do so efficiently. The obvious example is bound-methods, but classes are at least as important. cls(*args) -> cls.new(cls, *args) -> cls.init(self, *args) But tpnew and tpinit take the "cls" and "self" as separate arguments, not as part of *args. So I don't see why you need PYVECTORCALLARGUMENTSOFFSET for this.

Here's some (untested) code for an implementation of vectorcall for object subtypes implemented in Python. It uses PY_VECTORCALL_ARGUMENTS_OFFSET to save memory allocation when calling the init method.

https://github.com/python/cpython/commit/9ff46e3ba0747f386f9519933910d63d5caae6ee#diff-c3cf251f16d5a03a9e7d4639f2d6f998R3820

Cheers, Mark.



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